Helferella oborili, Bílý, Svatopluk & Nakládal, Oto, 2010

Bílý, Svatopluk & Nakládal, Oto, 2010, Helferella oborili sp. nov. from Indonesia (Coleoptera: Buprestidae: Polycestinae: Haplostethini), Zootaxa 2350, pp. 66-68 : 66-68

Helferella oborili sp. nov.

( Figs. 1–5 )

Type specimens. Holotype (3): “ Indonesia, Tanimbar is.[Prov. Papua], Yamdena ISL., 20 km NE of Saumlaki, 150 m, 1.–31.i.2007, M. Obořil lgt.”; allotype (Ƥ):same data; paratypes (70 33, 49 ƤƤ): same data. Holotype, allotype and 30 paratypes deposited in the National Museum, Prague ( Czech Republic), 89 paratypes deposited in the collection of M. Obořil (Brno, Czech Republic).

Diagnosis. Very small (2.40–3.20 mm), convex, subparallel, moderately lustrous species ( Fig. 1 ); dorsal surface black with very slight brass tinge (male only); ventral surface lustrous, black in both sexes; head and ventral surface glabrous, pronotum and elytra with extremely fine, sparse, nearly invisible, white pubescence.

Description of the male holotype ( Fig. 1 ). Head small, partly retracted into prothorax; frontoclypeus angularly produced between eyes, slightly emarginate anteriorly; frons moderately convex, slightly grooved medially, vertex convex, about 1.8 times as wide as width of eye; eyes small, narrowly reniform, distinctly projecting beyond outline of head, inner margins converging dorsally; antennae rather long, reaching posterior fourth of pronotal length when laid along side; scape robust, pyriform, slightly curved, about 2.5 times as long as wide; pedicel spherical, only slightly narrower than scape; antennomere 3 somewhat claviform, slender, twice as long as wide; antennomere 4 subtriangular, subequal in length to 3; 5–10 obtusely triangular, as wide as long; 11 ovoid, twice as long as wide; sculpture of head consisting of fine, simple punctures, separated by slightly more than their diameter.

Pronotum strongly convex, 1.52 times as wide as long, widest at midlength or slightly posteriad of midlength; anterior margin shallowly concave, nearly straight at middle; posterior margin finely biarcuate; lateral margins strongly arcuate along basal half, then attenuate to arcuate anterior angles; prelateral carina well-developed, nearly reaching anterolateral angles; sublateral groove for antennae in repose well-developed ( Fig. 3 ); sculpture consisting of dense, very fine, simple punctures, separated by somewhat more than their diameter; basal portion also with very fine, transverse rugae. Scutellum small, subtriangular, about 1.5 times as long as wide.

Elytra regularly convex, distinctly narrower than pronotum, 1.50 times as long as wide, widest part at midlength; humeral swellings small but distinct; basal transverse depression deep nearly reaching scutellum; epipleura welldeveloped only at subhumeral portion of elytra, then gradually merging with lateral margin; each elytron widely, separately rounded apically; punctation finer, somewhat sparser than that on pronotum.

Ventral surface ( Fig. 2 ) rather lustrous, abdominal ventrites finely punctate, prosternum asperate; prosternal process wide, strongly convex, slightly narrowed posteriorly to widely rounded posterior margin; suture between ventrites 1 and 2 indistinct at middle; anal ventrite three times as wide as long with fine depressions at lateroposterior angles, posterior margin widely, regularly rounded ( Fig. 4 ). Legs relatively short; femora fusiform; tibiae finely sinuate; tarsi short, slightly more than half as long as tibiae, tarsomeres 1–4 with yellow adhesive pads; distal tarsomere (including claws) as long as tarsomeres 1–4 together; tarsal claws yellow, simple, slightly hook-shaped, somewhat enlarged basally.

Aedeagus ( Fig. 5 ) short, flattened, strongly enlarged posteriorly; parameres widely open, sharply pointed apically ( Fig. 5 a); median lobe nearly spoon-shaped, enlarged preapically, pointed at apex ( Fig. 5 b).

Sexual dimorphism. The female differs from the male only by the somewhat larger body, black colouration without (or with nearly indistinct) metallic lustre and by less rounded, nearly truncate anal ventrite.

Measurements. Length: 2.40–3.20 mm (holotype 2.65 mm); width: 0.90–1.25 mm (holotype 1.00 mm).

Variability. No variability was observed except for size, sexual dimorphism and proportions of pronotum and elytra: pronotum 1.48–1.55 times as wide as long, elytra 1.48–1.60 times as long as wide.

Biology. Unknown; all specimens were reared from fallen twigs (diameter 7–30 mm) under a tree which likely belongs to the family Fabaceae .

Distribution. Indonesia, Prov. Papua, Tanimbar Isls., Yamdena Is.

Etymology. This species is named after the collector of type specimens, Martin Obořil (Brno, Czech Republic).

Differential diagnosis. Accordingly to Bellamy (2008), the genus Helferella is comprised of 14 species distributed in Australia (8 spp.), Fiji (3 spp.), Papua New Guinea (2 spp.) and the Philippines (1 sp.). Helferella oborili sp. nov. differs from both nearly-sympatric species distributed in Papua New Guinea by the following characters: from H. dianae Cobos, 1957 by much shorter and sparser dorsal pubescence, nearly hairless antennae, less acuminated elytra and by the shape of male genitalia (parameres arcuate laterally and obtusely pointed apically, median lobe narrowly pointed apically in H. dianae – see Cobos, 1957, fig. 3); from H. papuae Bellamy, 1990 by grooved frons, shape of pronotum widest at basal fourth in H. papuae , lacking blue reflection of dorsal surface and by the shape of male genitalia (subparallel parameres in H. papuae – see Bellamy, 1990, fig. 15).

Figures

FIGURES 1 – 5. Helferella oborili sp. nov. 1, holotype, male, dorsal view, 2.65 mm; 2, paratype, male, ventral view, 2.60 mm; 3, the same paratype, prosternum; 4, the same paratype, anal ventrite; 5, the same paratype, aedeagus (a, parameres, b, median lobe); scale bar: 0.5 mm.